There has been developed a light distribution variable headlamp (ADB: Adaptive Driving Beam) which partially blocks high beam when an imaging camera, which images the area ahead of a vehicle, detects a preceding vehicle or an oncoming vehicle so as to prevent the high beam of a vehicle from dazzling the driver of the preceding vehicle or the oncoming vehicle at night. Further, there has been known a technique for changing the luminance distribution or the illumination range of a light distribution pattern according to surrounding environments or road situations.
For example, a vehicle lamp tool is mainly constituted of an excitation light source, a light deflector, which scans, in a two-dimensional manner (in a horizontal direction and a vertical direction), an excitation light ray from the excitation light source that has been condensed by a condensing lens, a wavelength conversion member on which a two-dimensional image corresponding to a predetermined light distribution pattern is drawn by the excitation light ray, and a projection lens which projects in front the two-dimensional image drawn on the wavelength conversion member (refer to Japanese Patent Application Laid-Open No. 2015-153646).
The light deflector is a 1 axis non-resonant-1 axis resonance type, and is placed in a state in which a first axis is included in a vertical plane and a second axis is included in a horizontal plane. This enables the light deflector to easily form a predetermined light distribution pattern that is wide in the horizontal direction and narrow in the vertical direction, which is required of a vehicle lamp tool.
Further, the vehicle lamp tool has a vehicle speed sensor, and determines whether the vehicle is traveling or at a halt based on a detection result of the vehicle speed sensor. A MEMS power circuit controls a piezoelectric actuator of the light deflector to change the light distribution pattern according to whether it is determined that the vehicle is traveling or at a halt.